JP6097151B2 - Method for producing gas separation membrane - Google Patents

Description

  The present invention relates to a method for producing a gas separation membrane, and more particularly to a method for producing a gas separation membrane having a porous membrane and a polymer layer.

  For example, a gas membrane separation process, which is a process for realizing energy saving, is used when carbon dioxide is separated from synthesis gas synthesized in a large-scale plant such as hydrogen production or urea production, natural gas, or exhaust gas. A porous membrane is used as a base material for the gas separation membrane in the gas membrane separation process in order to increase mechanical strength.

  The carbon dioxide separation membrane described in Patent Document 1 has a carbon dioxide separation activity by applying a coating liquid on a porous membrane and removing the medium contained in the coating layer by drying the obtained coating layer. It is manufactured by a method of laminating a polymer layer on a porous film.

  In order to improve the productivity of the gas separation membrane, it is desired to mass-produce the separation membrane by, for example, applying a coating liquid and then continuously drying it with a roll support type drying furnace or the like. However, a porous membrane that is easily plastically deformed by tension stretches during high-temperature drying after application of the coating solution, so it is necessary to dry at a low temperature for a long time, and it is not easy to improve the productivity of the gas separation membrane. .

JP 2009-195900

  Accordingly, an object of the present invention is to suppress the elongation of the porous membrane during drying and improve the productivity of the gas separation membrane in a method for producing a gas separation membrane having a porous membrane and a polymer layer.

A method for producing a gas separation membrane according to the present invention that achieves the above object is a method for producing a gas separation membrane that selectively permeates carbon dioxide, and includes a substance that reversibly reacts with carbon dioxide, a hydrophilic polymer, and a medium. Obtained in the first step of coating the coating liquid on one side of the peeling support, the second step of laminating the porous film on the coating layer side of the laminate obtained in the first step, and the second step. A third step of removing the medium contained in the coating layer of the laminated body to make the coating layer a polymer layer, and a fourth step of peeling the peeling support from the laminated body obtained in the third step. And the following peel strength (X, Y) measured by the peel adhesion strength test method at a peel speed of 300 mm / min specified in JIS K-6854-2 is in the relationship of the following formula: And
X: 180 degree peel strength between the polymer layer and the porous film in the laminate obtained in the third step [N / 25 mm]
Y: 180 degree peel strength between the polymer layer and the peeling support [N / 25 mm]
X> Y and 0.1 ≦ Y ≦ 50

Further, according to the present invention, the first step of applying a coating liquid containing a substance reversibly reacting with carbon dioxide, a hydrophilic polymer, and a medium to one surface side of the peeling support, and the first step are obtained. A second step of laminating a porous film on the coating layer side of the laminated body, and a third step of removing the medium contained in the coating layer to form a polymer layer in the coating layer of the laminated body obtained in the second step; Gas separation characterized in that the following peel strength measured by the peel adhesion strength test method at a peel speed of 300 mm / min specified in JIS K-6854-2 has the following relationship: A method for producing a laminate for film production is also provided.
X: 180 degree peel strength between the polymer layer and the porous film in the laminate obtained in the third step [N / 25 mm]
Y: 180 degree peel strength between the polymer layer and the peeling support [N / 25 mm]
X> Y and 0.1 ≦ Y ≦ 50

  Here, the content of the medium contained in the coating layer in the laminate obtained in the second step is preferably in the range of 40 wt% to 99 wt%.

  As the hydrophilic polymer, a polyvinyl alcohol-polyacrylic acid copolymer is preferable.

  The peeling support is preferably a non-porous film. As the non-porous film, a polyethylene terephthalate film is preferable.

  The medium is preferably at least one selected from the group consisting of water, methanol, ethanol, 1-propanol and 2-propanol.

  The content of the medium contained in the polymer layer in the laminate obtained in the third step is preferably in the range of 1% by weight to 34% by weight.

  The medium is preferably removed by evaporation of the medium at a temperature in the range of 80 ° C to 200 ° C.

  The first step, the second step and the third step are preferably carried out continuously.

  Alternatively, the laminate obtained in the third step may be temporarily wound into a roll shape, and the roll-like laminate body may be unwound and used for the fourth step.

  The first step is preferably performed by continuous conveyance, the second step is also preferably performed by continuous conveyance, and the third step is also preferably performed by continuous conveyance.

  In the production method of the present invention, a coating liquid containing a substance that reacts reversibly with carbon dioxide, a hydrophilic polymer, and a medium is applied to one side of the peeling support, and then a porous film is laminated on the coating layer side. After removing the medium contained in the coating layer and making the coating layer into a polymer layer, the peeling support is peeled off from the obtained laminate, thereby suppressing the elongation of the porous film during drying and gas separation. Membrane productivity can be improved. Further, even when the mechanical strength of the polymer layer is low, it can be expected that the polymer layer is prevented from being damaged during peeling.

The manufacturing method which concerns on this invention which implements a 1st process, a 2nd process, and a 3rd process continuously, and each process performs all by continuous conveyance and winds up the laminated body obtained at a 3rd process once in roll shape. It is the schematic which shows an example of the manufacturing apparatus which implements. It is the schematic which shows an example of the manufacturing apparatus which implements the manufacturing method based on this invention which unwinds the laminated body wound up by the 3rd process, and performs a 4th process by continuous conveyance. It is the schematic which shows the carbon dioxide separator used for the measurement of the carbon dioxide separation performance in an Example.

  Hereinafter, the production method according to the present invention will be described in detail, but the present invention is not limited to these embodiments, and various modifications are possible within the scope shown in the claims, and each is disclosed in different embodiments. Embodiments obtained by appropriately combining the technical means provided are also included in the technical scope of the present invention.

  The method for producing a gas separation membrane according to the present invention will be described for each step. First, as a 1st process, the coating liquid containing the substance which reacts reversibly with a carbon dioxide, a hydrophilic polymer, and a medium is apply | coated to the one surface side of the peeling support body, and a 1st laminated body is produced.

  Examples of the substance that reacts reversibly with carbon dioxide include cesium carbonate, cesium bicarbonate, cesium hydroxide, rubidium carbonate, rubidium bicarbonate, rubidium hydroxide, and alkali metal ions.

  Examples of the hydrophilic polymer include polyvinyl alcohol (PVA), polyethylene glycol, polyethylene oxide, polyacrylic acid (PAA), polysulfonic acid, polyacrylamide, polyallylamine, polyethyleneimine, PVA-PAA copolymer, and methacrylic acid-vinyl. Examples thereof include a benzene copolymer and a sulfonic acid-PAA copolymer. Among these, a PVA-PAA copolymer is preferably used.

  As the medium, alcohols such as methanol, ethanol, 1-propanol and 2-propanol, hydrocarbons such as toluene, xylene and hexane, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, N-methylpyrrolidone, N, N-dimethyl Examples include aprotic polar solvents such as acetamide and N, N-dimethylformamide, water, and the like, and these can be used alone or in combination within a compatible range as a medium. Among these, a medium containing at least one selected from the group consisting of alcohol such as methanol, ethanol, 1-propanol, 2-propanol, and water is preferable.

  The peeling support used in the present invention is not particularly limited, and conventionally known ones having heat resistance can be used. For example, polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polycarbonate, polyimide , Polyether ether ketone, polyimide, polyether imide, polyamide, aramid, polyphenylene sulfide, glass, fluororesin, polyvinyl chloride, polyvinylidene chloride, cellulosic resin, silicone resin, etc. Film. Among these, a PET film is preferable from the viewpoints of surface treatment properties, peelability, heat resistance, and the like. The peeling support may be subjected to a release treatment, a mirror finish treatment, an embossing treatment, a matte treatment or the like, if necessary.

  180 degree peel strength between the polymer layer and the peeling support (by a corona treatment on the peeling support or a coating with a release agent (hereinafter sometimes referred to as “molding treatment”)). Y) can be adjusted. If the strength of the corona treatment is increased, the peel strength Y tends to decrease.

  The weight ratio of the substance that reacts reversibly with carbon dioxide to the total weight of the substance that reacts reversibly with carbon dioxide and the hydrophilic polymer is preferably in the range of 20% by weight to 90% by weight.

  A method for applying the coating liquid to the peeling support is not particularly limited and may be appropriately selected depending on the intended purpose. For example, spin coating, bar coating, die coating, blade coating, air knife coating, gravure coating , Roll coating application, spray application, dip application, comma roll method, kiss coating method, screen printing, inkjet printing and the like. The coating film thickness of the coating liquid is preferably 10 μm to 1000 μm, more preferably 50 μm to 1000 μm, and still more preferably 100 μm to 500 μm. The adjustment of the coating film thickness can be controlled by the coating film forming speed (for example, the conveyance speed of the peeling support), the concentration of the coating liquid, the discharge amount of the coating liquid, and the like.

  Moreover, it is preferable to apply the coating solution a plurality of times. When the target number of times of application is N, a laminated film obtained by applying and drying the coating liquid on the peeling support N-1 times is used as the peeling support, so that the first step, the second step, and the third step. The polymer layer can be laminated N times by performing the process. For example, when there is a pinhole in one coating layer, the probability that the pinholes overlap with each other by applying a plurality of times becomes extremely low, so that the occurrence of pinholes in the polymer layer can be prevented.

  Next, as a second step, a porous film is laminated on the coating liquid side of the first laminate to produce a second laminate. In the production method of the present invention, the porous film is laminated before removing the medium from the coating layer, and after removing the medium from the coating layer, the peeling support is peeled off, so that the polymer layer is prevented from being damaged during peeling. .

  The porous membrane used in the present invention is preferably a polymer porous membrane, and the material thereof is a conventionally known polymer, for example, a polyolefin resin such as polyethylene or polypropylene, polytetrafluoroethylene (PTFE), polyvinyl fluoride. And various resins such as polystyrene, cellulose acetate, polyurethane, polyacrylonitrile, polysulfone, polyethersulfone, polyimide, polyaramid, etc., preferably PTFE, polysulfone, polyethersulfone, polyacrylonitrile. , Cellulose acetate, polyimide and the like are preferably used. Among these, PTFE is more preferable because it is easy to obtain a fine pore diameter, and because the porosity can be increased, the separation energy efficiency is good.

  The thickness of the porous membrane is not particularly limited, but from the viewpoint of mechanical strength, it is usually preferably in the range of 10 μm to 3000 μm, more preferably in the range of 10 μm to 500 μm, and still more preferably in the range of 15 μm to 150 μm. is there.

  The average pore diameter of the pores of the porous membrane is not particularly limited, but is preferably 10 μm or less, more preferably 0.1 μm or less. The porosity of the porous film is preferably in the range of 5% to 99%, more preferably in the range of 30% to 90%.

  By selecting the surface treatment such as corona treatment to the porous membrane and the pore size of the porous membrane, the 180 degree peel strength (X) between the polymer layer and the porous membrane in the laminate obtained in the third step can be adjusted. it can. If the strength of the corona treatment is increased, the peel strength X tends to decrease. Moreover, if a porous film having a small pore diameter is selected, the peel strength X tends to be improved.

  Next, as a third step, the medium is removed from the coating layer of the coating liquid to produce a third laminate. A method for removing the medium is not particularly limited, and a conventionally known method can be used, but a method of evaporating and removing the medium by drying the coating film by ventilating heated air or the like is preferable. For example, the laminate is carried into a ventilation drying furnace adjusted to a predetermined temperature and a predetermined humidity, and the medium is evaporated and removed from the coating layer. In the present invention, the layer from which the medium is removed from the coating layer is referred to as a polymer layer.

  What is necessary is just to determine a drying temperature suitably with the medium of a coating liquid, the kind of porous membrane, and the support body for peeling. In general, the temperature is preferably higher than the freezing point of the medium and lower than the melting point of the porous membrane and the peeling support, and is generally in the range of 80 ° C to 200 ° C.

  The medium removal operation is performed until the medium contained in the coating layer becomes a predetermined concentration or less. Specifically, it is preferable to carry out until the content rate of the medium contained in the coating layer in the laminate obtained in the third step reaches a range of 1% by weight to 34% by weight.

When the 180 degree peel strength [N / 25 mm] between the polymer layer and the porous film in the laminate in the third step is X, and the 180 degree peel strength [N / 25 mm] between the polymer layer and the peeling support is Y, X and Y have the following relationship.
X> Y and 0.1 ≦ Y ≦ 50

  Next, as a fourth step, the peeling support is peeled from the third laminate to obtain a gas separation membrane in which the porous membrane and the polymer layer are laminated.

  There is no limitation in particular in the method of peeling a peeling support body from a 3rd laminated body, A conventionally well-known method can be used. For example, using a pair of peeling rollers, after passing through the nip portion of the pair of peeling rollers, the gas separation film in which the porous film and the polymer layer are laminated and the peeling support are conveyed in different directions, respectively. The support for peeling is peeled from the laminate.

  From the viewpoint of preventing peeling marks and wrinkles from being generated on the gas separation membrane when peeling the peeling support from the third laminate, it is necessary to apply tension to each of the gas separation membrane and the peeling support. preferable. In addition, the angle θ (shown in FIG. 1) between the transport direction of the gas separation membrane and the transport direction of the peeling support after passing through the nip portion of the pair of peeling rollers is 30 ° to 180 °. Preferably, it is 90 ° to 180 °, more preferably 120 ° to 180 °.

  Of course, it is possible to change the transport direction between the gas separation membrane and the peeling support using a single peeling roller so that the peeling support is peeled off from the gas separation membrane.

  Of course, the gas separation membrane produced by the production method of the present invention may be used after being laminated with another support after peeling the peeling support from the gas separation membrane.

  The gas separation membrane produced by the production method of the present invention is expected to be used in various fields. For example, synthesis gas synthesized in large-scale plants such as hydrogen production and urea production, natural gas, and exhaust gas from exhaust gas. It is preferably used for separating carbon.

  FIG. 1 is a schematic diagram showing an example of a manufacturing apparatus that performs the manufacturing method according to the present invention. The manufacturing apparatus shown in FIG. 1 includes a first supply unit 1 and a second supply unit 2 that continuously unwind a porous film 11 and a peeling support 12 wound in a roll, respectively, a laminating roller pair 3, The coating part 4 which apply | coats the coating liquid 41 which comprises an application layer, the drying apparatus 5, and the winding part 6 which winds up the 3rd laminated body 15 in roll shape are provided.

  In the manufacturing apparatus having such a configuration, the peeling support 12 is unwound from the second supply unit 2. Next, in the coating unit 4, the coating liquid 41 constituting the polymer layer is coated on the peeling support 12 to form the first laminate 13. The porous film 11 is unwound from the first supply unit 1, and the porous film 11 and the first laminated body 13 are laminated by the laminating roller pair 3 to form a second laminated body 14. And the 2nd laminated body 14 is conveyed to the drying apparatus 5, and is dried. As a result, the medium is evaporated and removed from the coating layer of the coating liquid 41, and a polymer layer (not shown) is laminated between the porous film 11 and the peeling support 12 to form the third laminate 15. Then, the 3rd laminated body 15 is wound up by the winding part 6 in roll shape.

  The porous film 11 and the peeling support 12 are continuously conveyed from the supply unit to the winding unit by the rotation of the laminating roller pair 3 and the winding core of the winding unit 6. During this time, the guide roller may be driven to rotate, and the traveling of the porous film 11 and the peeling support 12 may be assisted.

  FIG. 2 is a schematic diagram showing an example of a process of peeling the peeling support from the third laminated body in the manufacturing apparatus that performs the manufacturing method according to the present invention. The manufacturing apparatus shown in FIG. 2 rolls the supply unit 7 for continuously unwinding the third laminated body 15 wound in a roll shape, the separation roller pair 8, the gas separation membrane 16, and the separation support 12. The 1st winding part 9 and the 2nd winding part 10 which wind up in the shape are provided.

  In the manufacturing apparatus having such a configuration, the third stacked body 15 is unwound from the supply unit 7. Then, the peeling support 12 is peeled from the third laminated body 15 by the peeling roller pair 8, and the gas separation film 16 and the peeling support 12 are separated into the first winding part 9 and the second winding part 10. Each is wound into a roll. In the manufacturing apparatus shown in FIG. 2, the angle θ between the transport direction of the gas separation membrane 16 and the transport direction of the peeling support 12 after passing through the nip portion N is fixed. It may be variable.

Example 1
4.3 parts by weight of a PVA-PAA copolymer (“SS gel” manufactured by Sumitomo Seika Co., Ltd.), 10.0 parts by weight of cesium carbonate and water were mixed to prepare a coating solution. Then, after coating on a PET peeling support ("PET38T157" manufactured by Lintec Co., Ltd., thickness 38μm, mold release treatment), a PTFE porous film ("WPW-045-80" manufactured by Sumitomo Electric Co., Ltd., pore diameter 0.45μm) is laminated. Thus, a second laminate was obtained. It was dried at a temperature of 120 ° C. to evaporate and remove the medium from the coating layer to obtain a third laminate. Then, the support for peeling was peeled from the 3rd laminated body, and the gas separation membrane was obtained.
The carbon dioxide separation performance of the obtained gas separation membrane was measured by the following method. The measurement results are shown in Table 1.

(Measurement of carbon dioxide separation performance)
The gas separation membrane obtained in Example 1 was used as the gas separation membrane 50, and this was fixed between the supply side 52 and the permeation side 53 of the stainless carbon dioxide separation membrane module 51. A carbon dioxide separator including one carbon dioxide separation membrane module 51 is shown in FIG. Using such a carbon dioxide separator, carbon dioxide separation was performed as follows.
A raw material gas (CO ₂ : 25%, N ₂ : 37%, H ₂ O: 39%) is supplied to the supply side 52 of the carbon dioxide separation membrane module 51 at a flow rate of 3.64 × 10 ⁻² mol / min. Sweep gas (H ₂ O vapor) was supplied to the permeation side 53 of the carbon dioxide separation membrane module 51 at a flow rate of 1.39 × 10 ⁻² mol / min. Here, H ₂ O was adjusted so that water would be fed by the fixed liquid feed pumps 58 and 60, heated and evaporated, and the above mixing ratio and flow rate were obtained. The pressure on the supply side 52 was adjusted to 600 kPaA by a back pressure regulator 55 provided on the downstream side of the cooling trap 54 in the exhaust gas discharge path. Further, a back pressure regulator 59 is also provided between the cooling trap 56 and the gas chromatograph 57, thereby adjusting the pressure on the permeation side 53 to atmospheric pressure. By quantifying the gas flow rate after the water vapor in the sweep gas discharged from the permeate side 53 is removed by the cooling trap 56 based on the analysis result of the gas chromatograph 57, each of CO ₂ and N ₂ contained in the permeate gas is determined. Permeance (mol / m ² s kPa) was calculated, and CO ₂ / N ₂ selectivity was determined from the ratio. The results are shown in Table 1.

Example 2
A gas separation membrane was obtained in the same manner as in Example 1 except that “PET38E” (thickness: 38 μm, mold release treatment) manufactured by Lintec Corporation was used as the PET peeling support. And the carbon dioxide separation performance in the obtained gas separation membrane was measured by the same method as Example 1. The measurement results are shown in Table 1.

Example 3
A gas separation membrane was obtained in the same manner as in Example 1 except that “T100-100” (thickness: 100 μm) manufactured by Mitsubishi Plastics was used as the PET peeling support. And the carbon dioxide separation performance in the obtained gas separation membrane was measured by the same method as Example 1. The measurement results are shown in Table 1.

  According to the production method of the present invention, the elongation of the porous membrane at the time of drying is suppressed, and the productivity of the gas separation membrane having the porous membrane and the polymer layer can be improved, which is useful. Further, even when the mechanical strength of the polymer layer is low, it can be expected that the polymer layer is prevented from being damaged during peeling.

DESCRIPTION OF SYMBOLS 1 1st supply part 2 2nd supply part 3 Laminating roller pair 4 Application | coating part 5 Drying device 6 Peeling roller pair 7 1st winding part 8 2nd winding part 11 Porous film 12 Peeling support body 13 1st laminated body 14 Second laminated body 15 Third laminated body 16 Gas separation membrane 41 Coating liquid 50 Gas separation membrane 51 Carbon dioxide separation membrane module (52: supply side, 53: permeation side)
54, 56 Cooling trap 55, 59 Back pressure regulator 57 Gas chromatograph 58, 60 Liquid feed pump

Claims (14)

A method for producing a gas separation membrane that selectively permeates at least carbon dioxide,
A first step of applying a coating liquid containing a substance that reversibly reacts with carbon dioxide, a hydrophilic polymer, and a medium to one side of the support for peeling;
A second step of laminating a porous film on the coating layer side of the laminate obtained in the first step;
A third step of removing the medium contained in the coating layer from the layered product obtained in the second step and using the coating layer as a polymer layer;
A fourth step of peeling the support for peeling from the laminate obtained in the third step,
A method for producing a gas separation membrane, characterized in that the next peel strength measured by a peel adhesion strength test method at a peel speed of 300 mm / min specified in JIS K-6854-2 is in the relationship of the following formula: .
X: 180 degree peel strength between the polymer layer and the porous film in the laminate obtained in the third step [N / 25 mm]
Y: 180 degree peel strength between the polymer layer and the peeling support [N / 25 mm]
X> Y and 0.1 ≦ Y ≦ 50   The manufacturing method according to claim 1, wherein the laminate obtained in the third step is once wound up in a roll shape, and the wound laminate is unwound and used in the fourth step. A first step of applying a coating liquid containing a substance that reversibly reacts with carbon dioxide, a hydrophilic polymer, and a medium to one side of the support for peeling;
A second step of laminating a porous film on the coating layer side of the laminate obtained in the first step;
A third step of forming the coating layer of the laminate obtained in the second step into a polymer layer by removing the medium contained in the coating layer;
A laminate for producing a gas separation membrane, characterized in that the following peel strength measured by a peel adhesion strength test method at a peel speed of 300 mm / min defined in JIS K-6854-2 has the following relationship: Body manufacturing method.
X: 180 degree peel strength between the polymer layer and the porous film in the laminate obtained in the third step [N / 25 mm]
Y: 180 degree peel strength between the polymer layer and the peeling support [N / 25 mm]
X> Y and 0.1 ≦ Y ≦ 50   The production method according to any one of claims 1 to 3, wherein the content of the medium contained in the coating layer in the laminate obtained in the second step is in the range of 40 wt% to 99 wt%. .   The manufacturing method according to claim 1, wherein the hydrophilic polymer is a polyvinyl alcohol-polyacrylic acid copolymer.   The manufacturing method according to claim 1, wherein the peeling support is a non-porous film.   The manufacturing method according to claim 1, wherein the non-porous film is a polyethylene terephthalate film.   The production method according to claim 1, wherein the medium is at least one selected from the group consisting of water, methanol, ethanol, 1-propanol, and 2-propanol.   8. The method according to claim 1, wherein the content of the medium contained in the polymer layer in the laminate obtained in the third step is in the range of 1% by weight to 34% by weight. .   The method according to claim 1, wherein the removal of the medium is performed by evaporation of the medium in a temperature range of 80 ° C. to 200 ° C.   The manufacturing method according to any one of claims 1 to 10, wherein the first step, the second step, and the third step are continuously performed.   The manufacturing method according to claim 1, wherein the first step is performed by continuous conveyance.   The manufacturing method according to claim 1, wherein the second step is performed by continuous conveyance.   The manufacturing method according to claim 1, wherein the third step is performed by continuous conveyance.